U.S. patent number 8,202,067 [Application Number 12/447,756] was granted by the patent office on 2012-06-19 for oil pump for a refrigerating compressor.
This patent grant is currently assigned to Whirlpool S.A.. Invention is credited to Luiz Fabiano Jovita, Fabio Henrique Klein, Andrea Lopes.
United States Patent |
8,202,067 |
Klein , et al. |
June 19, 2012 |
Oil pump for a refrigerating compressor
Abstract
Oil pump for hermetic refrigerating compressor comprising a
tubular sleeve having an upper portion affixed to at least one of
the parts of crankshaft and rotor, and a lower portion having a
lower end immersed in the lubricant oil, said tubular sleeve being
provided with an inner surface presenting, along at least part of
its longitudinal extension, at least one helical groove upwardly
extending from the lower end; and a pump body disposed inside the
tubular sleeve and defining, with the adjacent helical groove of
the tubular sleeve, a lubricant oil ascending channel, said pump
body presenting a lower end portion mounted to one of the parts of
shell, cylinder block and stator, so as to be freely displaced
within the tubular sleeve, in radial directions orthogonal to the
crankshaft and rotatively locked in relation to the rotor.
Inventors: |
Klein; Fabio Henrique
(Joinville, BR), Jovita; Luiz Fabiano (Joinville,
BR), Lopes; Andrea (Joinville, BR) |
Assignee: |
Whirlpool S.A. (Sao Paulo-Sp,
BR)
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Family
ID: |
38926396 |
Appl.
No.: |
12/447,756 |
Filed: |
October 24, 2007 |
PCT
Filed: |
October 24, 2007 |
PCT No.: |
PCT/BR2007/000290 |
371(c)(1),(2),(4) Date: |
April 29, 2009 |
PCT
Pub. No.: |
WO2008/052297 |
PCT
Pub. Date: |
May 08, 2008 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20100074771 A1 |
Mar 25, 2010 |
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Foreign Application Priority Data
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Oct 31, 2006 [BR] |
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0604908 |
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Current U.S.
Class: |
417/410.3;
417/366; 417/372 |
Current CPC
Class: |
F04B
39/0246 (20130101); F04B 39/0261 (20130101) |
Current International
Class: |
F04B
37/14 (20060101) |
Field of
Search: |
;417/366,363,902,410.3,372,423.13 ;184/6.16,6.18
;415/111,113,175,176 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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0728946 |
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Aug 1996 |
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EP |
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WO-93/22557 |
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Nov 1993 |
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WO |
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WO-96/29516 |
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Sep 1996 |
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WO |
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WO-03/012297 |
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Feb 2003 |
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WO |
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WO-2005/047699 |
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May 2005 |
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WO |
|
Primary Examiner: Williams; Joseph L
Attorney, Agent or Firm: Gifford, Krass, Sprinkle, Anderson
& Citkowski, P.C.
Claims
The invention claimed is:
1. An oil pump for a refrigerating compressor presenting a shell
comprising in its interior: an oil reservoir containing lubricant
oil and carrying a cylinder block affixing the stator of a motor
provided with a rotor which rotates a crankshaft carrying, in a
lower end; and an oil pump immersed in the lubricant oil,
comprising: a tubular sleeve, having an upper portion affixed to at
least one of the parts of crankshaft and rotor, so as to rotate
therewith; a lower portion having a lower end immersed in the
lubricant oil, said tubular sleeve being provided with an inner
surface presenting, along at least part of its longitudinal
extension, at least one helical groove upwardly extending from the
lower end; and an elongated pump body, disposed in the interior of
the tubular sleeve, maintaining a certain radial gap in relation to
the latter and having an outer surface defining, with the adjacent
helical groove of the tubular sleeve, a lubricant oil ascending
channel, said pump body presenting a lower end portion projecting
beyond the lower end of the tubular sleeve and mounting means
mounting the lower end of said pump body to one of the parts of
shell, cylinder block, and stator, so as to be freely displaced in
the interior of the tubular sleeve, in radial directions orthogonal
to the crankshaft and rotatively locked in relation to the
rotor.
2. The oil pump, as set forth in claim 1, wherein the crankshaft
presents a tubular lower end portion inside which is mounted the
upper portion of the tubular sleeve.
3. The oil pump, as set forth in claim 2, wherein the tubular
sleeve is concentrically affixed to the crankshaft.
4. The oil pump, as set forth in claim 3, wherein the tubular lower
end portion of the crankshaft is provided with an inner thread, to
be coupled by an outer thread provided in the upper portion of the
tubular sleeve.
5. The oil pump, as set forth in claim 2, wherein the tubular
sleeve is directly and concentrically affixed to the rotor.
6. The oil pump, as set forth in claim 2, the tubular sleeve
externally carries, in its upper portion, a positioning stop to be
seated against the tubular lower end portion of the crankshaft,
limiting the relative axial positioning between the tubular sleeve
and the tubular lower end portion of the crankshaft.
7. The oil pump, as set forth in claim 6, wherein the positioning
stop comprises a peripheral flange incorporated, in a single piece,
to the upper portion of the tubular sleeve.
8. The oil pump, as set forth in claim 1, wherein it comprises a
supporting means having a first portion carrying the lower end
portion of the pump body and a second portion, through which the
supporting means is mounted to one of the parts of shell, cylinder
block and stator.
9. The oil pump, as set forth in claim 1, wherein the parts of
tubular sleeved and pump body present a circular cross-section.
10. The oil pump, as set forth in claim 9, wherein the parts of
tubular sleeve and pump body present a constant cross-section.
11. The oil pump, as set forth in claim 1, wherein the pump body
and the tubular sleeve are made in plastic material.
12. The oil pump, as set forth in claim 1, wherein the tubular
sleeve is in a single piece and the pump body is made in a single
piece.
13. The oil pump, as set forth in claim 1, wherein the tubular
sleeve is directly and concentrically affixed to the rotor.
14. An oil pump for a refrigerating compressor presenting a shell
comprising in its interior; an oil reservoir containing lubricant
oil and carrying a cylinder block affixing the stator of a motor
provided with a rotor which rotates a crankshaft carrying, in a
lower end; and an oil pump immersed in the lubricant oil,
comprising: a tubular sleeve, having an upper portion affixed to at
least one of the parts of crankshaft and rotor, so as to rotate
therewith; a lower portion having a lower end immersed in the
lubricant oil, said tubular sleeve being provided with an inner
surface presenting, along at least part of its longitudinal
extension, at least one helical groove upwardly extending from the
lower end; an elongated pump body, disposed in the interior of the
tubular sleeve, maintaining a certain radial gap in relation to the
latter and having an outer surface defining, with the adjacent
helical groove of the tubular sleeve, a lubricant oil ascending
channel, said pump body presenting a lower end portion projecting
beyond the lower end of the tubular sleeve and through which said
pump body is mounted to one of the parts of shell, cylinder block,
and stator, so as to be freely displaced in the interior of the
tubular sleeve, in radial directions orthogonal to the crankshaft
and rotatively locked in relation to the rotor; said crankshaft
presents a tubular lower end portion inside which is mounted the
upper portion of the tubular sleeve; said tubular sleeve is
directly and concentrically affixed to the rotor; and at least one
retaining element dispensed radially and having an end affixed in
one of the parts of said tubular sleeve and said rotor and another
end affixed to the other of said parts.
15. The oil pump, as set forth in claim 14, wherein the retaining
element has an end incorporated, in a single piece, to the tubular
sleeve and the other end seated and affixed against an adjacent end
face of the rotor.
16. The oil pump, as set forth in claim 15, wherein the retaining
element is affixed to the rotor by at least one of the means
defined by screws, glue, rivets, clamps.
17. An oil pump for a refrigerating compressor presenting a shell
comprising in its interior; an oil reservoir containing lubricant
oil and carrying a cylinder block affixing the stator of a motor
provided with a rotor which rotates a crankshaft carrying, in a
lower end; and an oil pump immersed in the lubricant oil,
comprising: a tubular sleeve, having an upper portion affixed to at
least one of the parts of crankshaft and rotor, so as to rotate
therewith; a lower portion having a lower end immersed in the
lubricant oil, said tubular sleeve being provided with an inner
surface presenting, along at least part of its longitudinal
extension, at least one helical groove upwardly extending from the
lower end; an elongated pump body, disposed in the interior of the
tubular sleeve, maintaining a certain radial gap in relation to the
latter and having an outer surface defining, with the adjacent
helical groove of the tubular sleeve, a lubricant oil ascending
channel, said pump body presenting a lower end portion projecting
beyond the lower end of the tubular sleeve and through which said
pump body is mounted to one of the parts of shell, cylinder block,
and stator, so as to be freely displaced in the interior of the
tubular sleeve, in radial directions orthogonal to the crankshaft
and rotatively locked in relation to the rotor; and said crankshaft
being provided, in its outer surface, with at least one oil outer
channel wherein the helical groove of the tubular sleeve presents
an upper end opened to the oil outer channel of the crankshaft.
18. The oil pump, as set forth in claim 17, wherein the upper end
of the helical groove is radially and directly opened to the oil
outer channel of the crankshaft.
19. The oil pump, as set forth in claim 17, wherein the upper end
of the helical groove is opened to a passage chamber defined in the
crankshaft, in fluid communication with the oil outer channel
thereof.
20. The oil pump, as set forth in claim 19, wherein the passage
chamber is defined in the interior of the crankshaft, between the
upper end portion of the pump body and the interior of the tubular
lower end portion of the crankshaft.
21. An oil pump for a refrigerating compressor presenting a shell
comprising in its interior; an oil reservoir containing lubricant
oil and carrying a cylinder block affixing the stator of a motor
provided with a rotor which rotates a crankshaft carrying, in a
lower end; and an oil pump immersed in the lubricant oil,
comprising: a tubular sleeve, having an upper portion affixed to at
least one of the parts of crankshaft and rotor, so as to rotate
therewith; a lower portion having a lower end immersed in the
lubricant oil, said tubular sleeve being provided with an inner
surface presenting, along at least part of its longitudinal
extension, at least one helical groove upwardly extending from the
lower end; an elongated pump body, disposed in the interior of the
tubular sleeve, maintaining a certain radial gap in relation to the
latter and having an outer surface defining, with the adjacent
helical groove of the tubular sleeve, a lubricant oil ascending
channel, said pump body presenting a lower end portion projecting
beyond the lower end of the tubular sleeve and through which said
pump body is mounted to one of the parts of shell, cylinder block,
and stator, so as to be freely displaced in the interior of the
tubular sleeve, in radial directions orthogonal to the crankshaft
and rotatively locked in relation to the rotor; a supporting means
having a first portion carrying the lower end portion, the pump
body and a second portion through which the supporting means is
mounted to one of the parts of shell cylinder block and stator; and
the parts defined by the lower end portion of the pump body and by
the first portion of the supporting being loosely fitted to each
other, so that the pump body can be freely displaced in radial
directions orthogonal to the crankshaft.
22. The oil pump, as set forth in claim 21, wherein the supporting
means comprises a rigid rod having the first portion loosely fitted
in a radial housing provided in the lower end portion of the pump
body, so as to support the latter.
23. The oil pump, as set forth in claim 22, and with the crankshaft
comprising: a tubular lower end portion having an inner wall,
wherein the radial housing presents an upper face which seats onto
the first portion of the rigid rod, and a lower face axially spaced
from the first portion of the rigid rod, by a value lower than that
of the distance between an upper end portion of the pump body and
the inner wall at of the tubular end portion of the crankshaft.
24. The oil pump, as set forth in claim 23, wherein the lower end
portion of the pump body defines a widened base provided with the
radial housing.
25. The oil pump, as set forth in claim 24, wherein the radial
housing is in the form of a diametral through hole.
26. The oil pump, as set forth in claim 22, wherein the rigid rod
has the second portion mounted to the stator.
27. The oil pump, as set forth in claim 22, wherein the rigid rod
presents a double "L"-shaped profile.
28. The oil pump, as set forth in claim 27, wherein the second "L"
portion of the rigid rod is provided with fixation means for
affixing said rigid rod to the stator.
29. The oil pump, as set forth in claim 22, wherein the rigid rod
is made in plastic material.
30. An oil pump for a refrigerating compressor presenting a shell
comprising in its interior; an oil reservoir containing lubricant
oil and carrying a cylinder block affixing the stator of a motor
provided with a rotor which rotates a crankshaft carrying, in a
lower end; and an oil pump immersed in the lubricant oil,
comprising: a tubular sleeve, having an upper portion affixed to at
least one of the parts of crankshaft and rotor, so as to rotate
therewith; a lower portion having a lower end immersed in the
lubricant oil, said tubular sleeve being provided with an inner
surface presenting, along at least part of its longitudinal
extension, at least one helical groove upwardly extending from the
lower end; an elongated pump body, disposed in the interior of the
tubular sleeve, maintaining a certain radial gap in relation to the
latter and having an outer surface defining, with the adjacent
helical groove of the tubular sleeve, a lubricant oil ascending
channel, said pump body presenting a lower end portion projecting
beyond the lower end of the tubular sleeve and through which said
pump body is mounted to one of the parts of shell, cylinder block,
and stator, so as to be freely displaced in the interior of the
tubular sleeve, in radial directions orthogonal to the crankshaft
and rotatively locked in relation to the rotor; the parts of the
tubular sleeve and the pump body a constant cross-section; and the
parts of tubular sleeve and the pump body present a respective
surface confronting with the surface of the other part, said
confronting surfaces having a conical profile.
31. An oil pump for a refrigerating compressor presenting a shell
comprising in its interior; an oil reservoir containing lubricant
oil and carrying a cylinder block affixing the stator of a motor
provided with a rotor which rotates a crankshaft carrying, in a
lower end; and an oil pump immersed in the lubricant oil,
comprising: a tubular sleeve, having an upper portion affixed to at
least one of the parts of crankshaft and rotor, so as to rotate
therewith; a lower portion having a lower end immersed in the
lubricant oil, said tubular sleeve being provided with an inner
surface presenting, along at least part of its longitudinal
extension, at least one helical groove upwardly extending from the
lower end; an elongated pump body, disposed in the interior of the
tubular sleeve, maintaining a certain radial gap in relation to the
latter and having an outer surface defining, with the adjacent
helical groove of the tubular sleeve, a lubricant oil ascending
channel, said pump body presenting a lower end portion projecting
beyond the lower end of the tubular sleeve and through which said
pump body is mounted to one of the parts of shell, cylinder block,
and stator, so as to be freely displaced in the interior of the
tubular sleeve, in radial directions orthogonal to the crankshaft
and rotatively locked in relation to the rotor; said tubular sleeve
being directly and concentrically affixed to said rotor; and at
least one rotating element disposed radially and having an end
affixed to one of the parts of the tubular sleeve and the rotor and
an opposite end affixed to the other of said parts.
32. The oil pump, as set forth in claim 31, wherein the rotating
element has an end incorporated, in a single piece, to the tubular
sleeve and the other end seated and affixed against an adjacent end
face of the rotor.
33. The oil pump, as set forth in claim 32, wherein the rotating
element is affixed to the rotor by at least one of the means
defined by screws, glue, rivets, clamps.
Description
This application is a US National Phase Application under 35 U.S.C.
.sctn.371 of International Patent Application No. PCT/BR2007/000290
filed Oct. 24, 2007, which claims priority to and the benefit of
Brazilian Patent Application No. PI0604908-7, filed Oct. 31, 2006,
each of which are hereby incorporated by reference in their
entireties. The International Application published as WO
2008/052297 Al on May 8, 2008.
FIELD OF THE INVENTION
The present invention refers to an oil pump for a refrigerating
compressor of the type which comprises, in the interior of a
hermetic shell, a motor which carries a crankshaft having an upper
end for driving a refrigerant gas pumping mechanism of the
compressor, and a lower end carrying an oil pump immersed in a
lubricant oil contained in an oil reservoir defined in the interior
of the shell.
BACKGROUND OF THE INVENTION
An important factor for the adequate operation of most
refrigerating compressors is the adequate lubrication of the
components thereof which have a relative movement between each
other. The lubrication is obtained by pumping lubricant oil
provided in an oil reservoir defined in the interior of a generally
hermetic shell of said compressors, in a lower portion of said
shell. This oil is pumped until reaching the parts with relative
movement of the compressor, wherefrom said oil returns, for
example, by gravity, to the oil reservoir.
In some known constructions, the compressor comprises a generally
vertical crankshaft that carries a lubricant oil pump, which
conducts said oil to the compressor parts to be lubricated, using
the rotation of said crankshaft. In these constructions, the oil is
pumped from the oil reservoir by spinning and mechanical
dragging.
In this constructions, the crankshaft presents a portion of its
extension provided, externally (WO2005/047699) or internally
(WO96/29516), with helical grooves which conduct the lubricant oil
from the oil reservoir to the relatively moving parts of the
compressor distant from the oil reservoir.
In the solution WO2005/047699, a tubular sleeve is provided around
part of the crankshaft which presents the helical grooves, said
tubular sleeve being attached to the compressor shell or to the
stator.
The solution WO96/29516 presents the crankshaft having part of its
extension defining a conduct inside which is mounted, with a radial
gap, a pump body, said solution presenting one of the parts of
inner wall of the tubular shaft and outer wall of the pump body
provided with helical grooves.
There are known some prior art solutions for oil pumping in
variable speed compressors. In these constructions (WO93/22557,
U.S. Pat. No. 6,450,785), the crankshaft inferiorly carries a pump
body provided with surface channels and which is internally
disposed in a tubular sleeve, one of the parts of pump body and
tubular sleeve being rotatively stationary in relation to the other
part, so as to allow a dragging effect on the oil being pumped by
centrifugal force, resulting from the rotation of the motor.
Solution WO93/22557 presents the pump body, which is externally
provided with helical grooves, affixed to the crankshaft, in order
to rotate therewith, the tubular sleeve being attached to the
electric motor, by a fixation rod, said tubular sleeve being
mounted around the pump body with a radial gap.
This solution allows friction wear to occur between the parts of
pump body and tubular sleeve, as well as mechanical losses, as a
result of the rigid fixation between said tubular sleeve and the
stator and of practically inevitable misalignments between the pump
body and the tubular sleeve.
Solution U.S. Pat. No. 6,450,785 presents the pump body externally
provided with helical grooves on its outer surface and inferiorly
attached to the electric motor stator through a fixation rod with a
"U"-shaped profile, and the tubular sleeve affixed to the
crankshaft of the compressor, so as to rotate therewith. This
solution presents a construction in which the fixation rod allows
only a certain angular movement of the pump body around axes
contained in the lower fixation plane of the pump body to the
fixation rod, said plane being orthogonal to the crankshaft of the
compressor. Thus, the fixation rod can be elastically deformed to
permit the pump body to incline to accommodate itself in the
interior of the tubular sleeve. However, as the pump body is not
free to be displaced, in its entirety, in directions orthogonal to
the crankshaft, it is not able to compensate for construction or
mounting misalignments, so as to occupy a position in which its
axis is concentric or parallel to the axis of the tubular
sleeve.
Although reducing the friction wear and losses, this known prior
art solution U.S. Pat. No. 6,450,785 also conducts to a certain
efficiency loss, particularly considering the inevitable
dimensional deviations of manufacture and mounting.
OBJECTS OF THE INVENTION
It is an object of the present invention to provide an oil pump for
a refrigerating compressor, which guarantees an adequate
lubrication of the compressor parts with relative movement, even in
low rotation speeds.
Another object of the present solution is to provide an oil pump
such as cited above, whose construction minimizes the problems
regarding wear and increase in the consumption of the parts which
compose said oil pump and subjected to concentricity loss and
friction.
It is a further object to provide an oil pump such as cited above,
which does not need accuracy for its construction and assembly.
Another object of the present invention is to provide an oil pump
such as cited above, which has a reduced cost and easy
construction.
SUMMARY OF THE INVENTION
The objects cited above, as well as other objects of the present
invention, are achieved by the provision of an oil pump for a
refrigerating compressor presenting a shell defining, in its
interior, an oil reservoir containing lubricant oil and carrying a
cylinder block affixing the stator of a motor provided with a rotor
which rotates a crankshaft carrying, in a lower end, an oil pump
immersed in the lubricant oil, said oil pump comprising: a tubular
sleeve, having an upper portion affixed to at least one of the
parts of crankshaft and rotor, so as to rotate therewith, and a
lower portion having a lower end immersed in the lubricant oil,
said tubular sleeve being provided with an inner surface
presenting, along at least part of its longitudinal extension, at
least one helical groove extending upwardly from the lower end; an
elongated pump body disposed in the interior of the tubular sleeve,
maintaining a certain radial gap in relation thereto and having an
outer surface defining, with the adjacent helical groove of the
tubular sleeve, a lubricant oil ascending channel, said pump body
presenting a lower end portion projecting beyond the lower end of
the tubular sleeve and through which said pump body is mounted to
one of the parts of shell, of cylinder block and stator, to be
freely displaced in the interior of the tubular sleeve, in radial
directions orthogonal to the crankshaft and rotatively locked in
relation to the rotor.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be described below with reference to the
enclosed drawings, given by way of example of an embodiment of the
invention and in which:
FIG. 1 represents a schematic longitudinal sectional view of a
refrigerating compressor with a vertical shaft, said compressor
presenting a crankshaft which inferiorly carries an oil pump
constructed according to the present invention, partially immersed
in the oil of an oil reservoir defined in a lower portion of the
shell of said compressor;
FIG. 2 represents a schematic view, such as the one of FIG. 1, but
offset in 90 degrees therefrom;
FIG. 3 represents a schematic enlarged view of the crankshaft
region in which is mounted the oil pump of the present invention,
such as illustrated in FIG. 1;
FIG. 4 represents a schematic perspective view of the crankshaft
securing the tubular sleeve of the pump of the present invention,
illustrating, in a partial longitudinal section, the crankshaft
region in which the tubular sleeve is mounted;
FIG. 5 represents a schematic exploded side view of the crankshaft,
of the electric motor and of the component parts of the oil pump of
the present invention;
FIG. 6 represents a schematic lower exploded perspective view of
the crankshaft, a stator cover, the component parts of the oil pump
of the present invention, and a fixation means for securing said
oil pump to the stator;
FIG. 7 represents a schematic lower perspective view of the
electric motor stator and of the oil pump of the present invention
affixed thereto;
FIG. 8 represents a schematic side view of the motor, taken from
the region in which the pump body of the oil pump of the present
invention is affixed to the stator;
FIG. 9 represents a schematic longitudinal sectional view of a
crankshaft securing an oil pump constructed according to the
present invention, for a construction in which the tubular sleeve
and pump body presents confronting conic surfaces;
FIG. 10 represents a schematic lower exploded perspective view of a
tubular sleeve of another construction for the oil pump of the
present invention, before its attachment to the rotor of the
compressor and before mounting it to the crankshaft of the
latter;
FIG. 11 represents a schematic perspective view of the tubular
sleeve illustrated in FIG. 10, after its fixation to the rotor of
the compressor; and
FIG. 12 represents a schematic longitudinal sectional view of the
oil pump construction illustrated in FIG. 11 in which the tubular
sleeve of said oil pump is partially mounted in the interior of the
crankshaft and attached to the electric motor rotor of the
compressor.
DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS
The present invention will be described for a reciprocating
hermetic compressor (for example, of the type applied to a
refrigerating system) presenting a generally hermetic shell 1,
housing a cylinder block 2 which defines a cylinder 3 within which
actuates a reciprocating piston (not illustrated), in a lower
portion of the shell 1 being defined an oil reservoir 4, wherefrom
the oil that lubricates the movable parts of the compressor is
pumped through an oil pump.
In the present construction described herein, the refrigerating
compressor is of the type which is driven by a crankshaft 10, which
moves the piston, said crankshaft 10 superiorly presenting an
eccentric portion 11 journalled to the cylinder block 2 and
carrying, in a lower end 12, the oil pump of the present invention,
which is operatively affixed to the rotor 6, so as to rotate
therewith, and presents a lower portion immersed in the lubricant
oil contained in the oil reservoir 4, and an upper portion which
maintains fluid communication with a helical external oil channel
13 provided in the crankshaft 10 and which takes the oil pumped by
the oil pump to the compressor parts to be lubricated.
The cylinder block 2 secures a stator 5 of an electric motor,
further including a rotor 6 attached to the crankshaft 10, so as to
rotate the latter upon operation of the motor.
According to the present invention, the oil pump comprises: a
tubular sleeve 20, having an upper portion 21 affixed to at least
one of the parts of crankshaft 10 and rotor 6, so as to rotate
therewith, and a lower portion 22 having a lower end 22a immersed
in the lubricant oil, said tubular sleeve 20 being provided with an
inner surface 23 in which is provided, along at least part of its
longitudinal extension, at least one helical groove 24 upwardly
extending from the lower end 22a.
The oil pump of the present invention further comprises an
elongated pump body 30 disposed in the interior of the tubular
sleeve 20, so that an outer surface of the pump body 30 maintains a
certain radial gap in relation to an adjacent confronting inner
surface of the tubular sleeve 20, said pump body 30 having a lower
end portion 31, projecting beyond the lower end 22a of the tubular
sleeve 20, to be affixed to at least one of the parts of shell 1,
cylinder block 2, and stator 5.
The tubular sleeve 20 is coupled to at least one of the parts of
rotor 6 and crankshaft 10, so as to be rotatively driven with the
part that carries it, upon rotation of the rotor 6, said movement
being provoked by operation of the electric motor, whilst the pump
body 30 remains rotatively fixed. The relative movement between the
tubular sleeve 20 and the pump body 30 makes the oil flow upwardly
from the oil reservoir 4, by mechanical dragging and centrifugal
force.
In a way of carrying out the present invention, at least the
tubular sleeve 20, in permanent contact with said crankshaft 10, is
provided in plastic material.
In a particular constructive form, the tubular sleeve 20 and the
pump body 30 are provided, for example, in plastic material.
The construction of the tubular sleeve 20 and pump body 30 in
plastic material facilitates the manufacture of these components.
Moreover, the manufacture in plastic material also minimizes the
heat transfer from the crankshaft 10 to the oil being pumped, due
to the low thermal conductivity of said material.
In one of the illustrated constructions (FIGS. 1-8 and 10-12), the
tubular sleeve 20 and the pump body 30 present a constant circular
cross-section along the respective longitudinal extension. However,
it should be understood that other constructions are possible
within the concept presented herein, such as a variable oblong
cross-sectional construction for said parts of tubular sleeve and
pump body.
In another way of carrying out the present invention illustrated in
FIG. 9, the parts of tubular sleeve 20 and pump body 30 present a
circular cross-section, but with a conical profile in their
confronting surfaces. In this construction, the wall thickness of
said tubular sleeve 20 ranges from a reduced thickness, adjacent to
its lower end 22a, in which the inner diameter of said tubular
sleeve 20 is the largest of this construction, to a greater wall
thickness in the region of an upper end 21a of the upper portion 21
of the tubular sleeve 20, in which the inner diameter of said
tubular sleeve 20 is the smallest of this construction. The
variations of wall thickness and inner diameter of the tubular
sleeve 20 are calculated so that they do not affect the pumping
efficiency of the present oil pump.
The solution of a constant circular cross-section presents the
advantage of presenting a better performance for the oil pumping,
although presenting higher difficulty to obtain the components when
these are made in plastic material. The construction in a conical
profile has the advantage of more facility to obtain the component
parts of the present oil pump when they are made in plastic
material.
In a complementary form, the pump body 30 of the illustrated
construction in FIG. 9 presents a conical profile having a larger
diameter adjacent to its lower end 31, and a smaller diameter
adjacent to its end 32, the diameter variation of said pump body 30
being gradual and continuous, as it occurs with the variation of
the inner diameter of the tubular sleeve 20. It should be noted
that the present solution further allows a stepped variation in at
least one of the parts of inner diameter of the tubular sleeve 20
and outer diameter of the pump body 30, without impairing the
pumping efficiency of the present pump.
According to the present invention, the tubular sleeve 20 presents
an inner surface wall 23, in which is provided, from the lower end
22a of said tubular sleeve 20, at least one helical groove 24
defining, with an adjacent confronting outer surface portion of the
pump body 30, lubricant oil ascending channels C which conduct oil
from the oil reservoir 4 and pumped by the present oil pump to the
parts with relative movement of the compressor. The pump body 30 is
mounted in the interior of the tubular sleeve 20, so as to be
freely displaced in the interior of the latter, in radial
directions orthogonal to the crankshaft 10 and rotatively fixed in
relation to the rotor 6.
Since the helical groove 24 is provided in the inner wall of the
tubular sleeve 20, the oil pump of the present invention presents
an effect of centrifugal force and mechanical dragging superior to
that of the prior art oil pump constructions.
In order not to alter the oil flow being upwardly drawn, the oil
channels, defined by the helical grooves 24 produced in the inner
surface 23 of the tubular sleeve 20, can be dimensioned so that the
thickness thereof varies proportionally to the thickness variation
of at least one of the parts of tubular sleeve 20 and pump body
30.
According to the present invention, the tubular sleeve 20 must be
attached to at least one of the parts of rotor 6 and crankshaft 10,
so as to be rotated by rotation of said rotor 6, directly by the
movement thereof or by rotation of the crankshaft 10.
In a way of carrying out the present invention, such as illustrated
in FIGS. 1-8, the tubular sleeve 20 is attached to the crankshaft
10, as described ahead, said crankshaft 10 presenting a tubular
lower end portion 14, inside which is mounted the upper portion 21
of the tubular sleeve 20.
In the embodiment of the present invention illustrated in FIGS.
9-12, the tubular sleeve 20 is directly affixed to the rotor 6,
although maintaining its upper portion 21 mounted in the interior
of the tubular lower end portion 14 of the crankshaft 10.
While not illustrated, it should be understood that the present
invention is not limited to a construction of crankshaft 10
internally mounting part of the tubular sleeve 20. The present
solution is applied to constructions in which the tubular sleeve 20
may not be fitted in the interior of a tubular lower end portion 14
of the crankshaft 10. Besides, the present solution is also applied
to constructions in which the crankshaft 10 externally affixes the
tubular sleeve 20 of the oil pump, independent of the mounting
arrangement of said tubular sleeve 20 in relation to the crankshaft
10.
In the constructions in which the crankshaft 10 does no present a
tubular lower end portion 14, the tubular sleeve 20 can be mounted
concentrical to the crankshaft 10, but externally thereto or also
receiving, in an upper tubular portion defined in said tubular
sleeve 20, an adjacent lower portion of said crankshaft 10.
Although the illustrated construction of tubular sleeve 20 and pump
body 30 presents each of said parts formed in a single piece, it
should be understood that both the tubular sleeve 20 and the pump
body 30 can be provided by a plurality of pieces to be mounted to
each other, each assembly of the plurality of pieces forming the
desired length for the respective part of tubular sleeve 20 and of
pump body 30.
According to a constructive form illustrated in FIGS. 1-8, the
tubular sleeve 20 of the present oil pump externally carries, in
its upper portion 21, a positioning stop 25, to be seated against
an adjacent portion of the crankshaft 10, limiting the relative
axial positioning between the tubular sleeve 20 and the tubular
lower end portion 14 of the crankshaft 10. For this embodiment of
the present invention, the positioning stop 25 limits the
introduction of the upper portion 21 of the tubular sleeve 20 in
the interior of the tubular lower end portion 14 of the crankshaft
10.
In this illustrated constructive option, the positioning stop 25
has the form of an annular peripheral flange 25a, externally
provided in the upper portion 21 of the tubular sleeve 20, for
example, incorporated in a single piece thereto.
In the illustrated construction, the peripheral flange 25a is
seated against an adjacent stop face of the tubular lower end
portion 14 of the crankshaft 10, in a condition in which the upper
portion 21 of the tubular sleeve 20 is mounted in the interior of
the tubular lower end portion 14 of the crankshaft 10. It should be
understood that the condition in which the tubular sleeve 20 is
mounted to the crankshaft 10 may be obtained by seating and
affixing said peripheral flange 25a against an adjacent end face of
the lower end 12 of the crankshaft 10, in the condition in which
said tubular sleeve 20 is mounted to said crankshaft 10.
In a particular construction of the present invention, illustrated
in the enclosed drawings, the peripheral flange 25a is annular and
continuous, being provided around the whole periphery of the
tubular sleeve 20. However, it should be understood that said
peripheral flange 25a may be provided occupying only part of the
peripheral extension of the tubular sleeve 20, or also provided in
the form of flange segments around part or the whole of said
peripheral extension of the tubular sleeve 20.
In another possible construction, the peripheral flange 25a is not
incorporated to the tubular sleeve 20, and may be, for example,
retained therein by an appropriate means, such as thread, fitting,
glue, etc., permitting a desired adjustment for the introduction of
the upper portion 21 inside the tubular lower end portion 14 of the
crankshaft 10, particularly permitting the adjustment of the
distance of the upper end 21a of said upper portion 21 of the
tubular sleeve 20 in relation to an inner wall 14a of the tubular
lower end portion 14 of the crankshaft 10 and which defines the
innermost portion thereof.
The present oil pump further comprises retaining means 40, which
affix the tubular sleeve 20 to at least one of the parts of rotor 6
and crankshaft 10, as described ahead.
For the construction illustrated in FIGS. 1-9, and in which the
tubular sleeve 20 is attached to the crankshaft 10, the retaining
means 40 comprise an inner thread 41, provided in an inner surface
portion of the tubular lower end portion 14 of the crankshaft 10,
to be engaged in an outer thread 42 provided in the upper portion
21 of the tubular sleeve 20, in an adjacent confronting portion of
the outer surface of the latter, each of said inner thread 41 and
outer thread 42 being defined along an extension of the respective
surface in which it is provided.
It should be understood that the retaining means 40 may present
other constructive forms for affixing the tubular sleeve 20 to the
crankshaft 10, such as rivet, glue, mechanical interference,
flexible fingers, external screwing, injection of the component in
the shaft itself, etc., these constructive options not being
limitative of the present invention.
In the constructive option illustrated in FIGS. 10-12, the tubular
sleeve 20 is directly and concentrically attached to the rotor 6,
through retaining means 40 provided in at least one of the parts of
tubular sleeve 20 and rotor 6, so as to actuate in the other of
said parts, affixing them to each other.
In a way of carrying out the present invention, the present oil
pump comprises at least one retaining element 43, radially disposed
and having an end 43a affixed in one of the parts of tubular sleeve
20 and rotor 6 and another end 43b affixed to the other of said
parts.
In a particular form of this solution, at least one retaining
element 43 has one of its ends incorporated, in a single piece, to
the tubular sleeve 20, the other end being seated and affixed
against an adjacent end face of the rotor 6, by at least one of the
means defined by screws, glue, rivets, clamps, etc.
In the constructive form illustrated in FIGS. 10-12, the tubular
sleeve 20 incorporates, in a single piece, from its upper portion
21, two pairs of retaining elements 43, in the form of radial
projections disposed around the tubular sleeve 20 to prevent force
resultants from acting thereon.
Each retaining element 43 has its other end 43b radially spaced
from the surface of the tubular sleeve 20 and seated against an
adjacent end face of the rotor 6, in a condition in which the
tubular sleeve 20 is mounted to the latter, so as to allow the
fixation of said tubular sleeve 20 to the rotor 6.
Each retaining element 43 is fixed to the rotor 6 by at least one
of the means defined by screws, glue, rivets, clamps, mechanical
interference, flexible fingers, etc.
In the construction illustrated in FIGS. 10-12, the retaining
elements 40 are symmetrically distributed around the outer surface
of the tubular sleeve 20, each presenting a respective retaining
hole 44 provided in the other end 43b of each respective retaining
element 43.
Upon mounting the tubular sleeve to the rotor 6 of this
construction, each retaining element 42 is conducted to a mounting
position to the rotor 6, so that each retaining hole 44 is aligned
with a retaining channel 6a produced in the rotor 6, to allow the
passage of a respective rivet or retaining screw 45, affixing the
tubular sleeve 20 to the rotor 6.
In this construction, the retaining elements 42 define a stop means
for introduction of the tubular sleeve 20 inside the tubular lower
end portion 14 of the crankshaft 10.
The construction of retaining means 40 in the form illustrated in
FIGS. 1-9, or in the form illustrated in FIGS. 10-12 of the
enclosed drawings is defined as a function of the characteristics
of the compressor in which the oil pump will be mounted. For
compressors presenting a crankshaft 10 already provided with an
inner thread portion defined in the tubular end portion 14 of said
crankshaft 10, such as illustrated in FIGS. 1-9, (as it occurs in
the compressors EG), the provision of the retaining means 40 in the
form of helical thread is more appropriate. However, regarding the
compressor constructions which do not present inner thread in the
tubular end portion 14 of the crankshaft 10, as is the case of
compressors EM, the retaining means 40 can present other
constructions, such as that illustrated in FIGS. 10-12. It should
be understood, however, that the constructions of retaining means
40 described and illustrated herein should not be considered as
limitative of the concept of affixing the tubular sleeve 20 to at
least one of the parts of crankshaft 10 and rotor 6.
In a constructive option in which the tubular sleeve 20 is
externally affixed to the crankshaft 10, the retaining means may
also have the form of cooperating threads, one of which provided,
for example, in the peripheral flange 25a and the other provided in
the adjacent end portion 12 of the crankshaft 10. In another
constructive form of retaining means within the concept presented
herein, this can be defined by an annular flange mounted to the
tubular sleeve 20 and to be seated against the rotor 6, or also in
the form of a projection affixed to the rotor 6 and presenting an
eye through which is fitted and affixed the tubular sleeve 20.
The mounting of the pump body 30 in the interior of the tubular
sleeve 20 is carried out so that an upper end portion 32 of the
pump body 30 is maintained with a certain axial spacing in relation
to the interior of the tubular end portion 14 of the crankshaft 10,
said axial spacing being particularly defined in relation to an
adjacent inner wall portion 14a of the crankshaft 10. This axial
spacing defines a passage chamber 16 in the interior of the
crankshaft 10, to which is opened an upper end 24a of each helical
groove 24 of each lubricant oil ascending channel C, permitting the
fluid communication between the lubricant oil of the oil reservoir
4 and said passage chamber 16. In some constructions, the passage
chamber 16 is also defined in the interior of the tubular sleeve
20, adjacent to the upper end 21 of the latter. In a construction
of the present invention, the passage chamber 16 maintains fluid
communication with the oil outer channel 13 of the crankshaft 10,
conducting lubricant oil to the compressor parts to be lubricated.
In this construction, the crankshaft 10 defines an auxiliary
reservoir in which is deposited the oil pumped from the oil
reservoir 4, wherefrom it is pumped, through oil channels provided
in the crankshaft 10, to the compressor parts away from the oil
reservoir 4. In a particular variant of this construction, the oil
reservoir is defined internal to the crankshaft 10.
In another embodiment of the present invention, the upper end 24a
of each helical groove 24 is radially and directly open to the oil
outer channel 13 of the crankshaft 10. In this case, the oil pumped
from the oil reservoir 4 is directly conducted to the oil outer
channel 13 of the crankshaft 10.
According to the present invention, the fixation of the pump body
30 to one of the parts of shell 1, cylinder block 2, and stator 5
is effected through a supporting means 50 having a first portion
51, which carries a lower end portion 31 of the pump body 30, and a
second portion 52, through which the supporting means 50 is mounted
to one of said parts of shell 1, cylinder block 2, and stator
5.
According to the present invention, the parts defined by the lower
end portion 31 of the pump body 30 and by the first portion 51 of
the supporting means 50 are loosely fitted to each other, so that
the pump body 30 can be freely displaced in radial directions
orthogonal to the crankshaft 10.
In the illustrated constructive form, the supporting means 50
comprises a rigid rod 50a having the first portion 51 loosely
fitted in a radial housing 33 provided in the lower end portion 31
of the pump body 30, so as to support the latter.
In a way of carrying out the present invention, the rigid rod 50a
is constructed in plastic material. The construction of the rigid
rod 50a in plastic material facilitates the manufacture of this
component. Furthermore, the construction in plastic material also
minimizes heat transfer from the crankshaft 10 to the oil being
pumped, as a function of the low thermal conductivity of said
material.
According to the illustrated appended figures, the lower end
portion 31 of the pump body 30 defines a widened base provided with
the radial housing 33, which is in the form of a diametral through
hole presenting an upper face 33a which seats onto the first
portion 51 of the rigid rod 50a, and a lower face 33b, axially
spaced from the first portion 51 of the rigid rod 50a by a value
lower than that of the axial distance between the upper end portion
32 of the pump body 30 and the inner wall 14a of the tubular end
portion 14 of the crankshaft 10, so as to prevent impacts between
said parts, during operation or displacements of the
compressor.
In the illustrated construction, the rigid rod 50a presents a
double L-shaped profile, having two consecutive and continuous "L"
portions, the two "L" portions of said rigid rod 50a being, in the
illustrated construction, interconnected with at least one
structural rib 53 between a base portion of one of the "L" portions
and an adjacent elevated portion of another of said "L"
portions.
It should be understood that the provision of the structural rib
53, which is a particular illustrated construction, should not be
limitative. In another embodiment of the present invention, the "L"
portions are provided in a single piece formed in a sufficiently
resistant material, so as not to require the provision of a
structural rib.
According to the present invention, one of the "L" portions
presents its respective elevated portion affixed to one of the
parts of shell 1, cylinder block 2 and stator 5 and, the other "L"
portion presents its respective base portion fitted in the radial
slot 33 of the pump body 30. In the illustrated construction, a
first "L" portion has its respective base portion fitted in the
radial slot 33 of the pump body 30 and is disposed inferiorly to a
second "L" portion, which is provided, in its respective elevated
portion, with fixation means 54, for example, in the form of
fingers 54a which are elastically deformed to be affixed to the
stator 5, particularly to a stator cover 60 of known construction
and usually mounted in a lower end of the stator, turned to the oil
reservoir 4.
According to the present invention, while a particular construction
of fixation rod 50a has been described, it should be understood
that the rod can present any profile which guarantees the desired
rigidity, its fixation to the stator 5 being carried out by other
fixation means 54 besides that illustrated in the form of fingers
54a, said fixation means 54 being, for example, glue, screw, rivet,
clamps, quick fitting ("snap-on"), welding, etc.
Although the concept presented herein has been described mainly
considering the oil pump construction illustrated, it should be
understood that this particular construction does not restrict the
applicability or scope of the present invention. The intention is
to protect the principle and not the specific application or
constructive form.
It should be understood that for any of the possible options for
constructing and mounting the tubular sleeve 20 to the rotor and/or
to the crankshaft 10 (internal or external to this), as well as the
provision and construction of the retaining means 40, the oil pump
of the present invention presents its pump body affixed to one of
the parts of shell 1, cylinder block 2 and stator 3 with a
supporting means, as cited above and which, for example, presents
the construction described and illustrated herein, but which should
not be considered as limitative of the presented concept.
* * * * *